NCR3 and cancer: In an alternative experimental set-up with independent blood donors we (1) diluted NK cell supernatants to decrease non-specific cytotoxicity (in the immunoglobulin G 1 (IgG1) control group) and (2) isolated HMGB1 by HPLC from the Nkp30-stimulated supernatants and added it to the IgG1 control supernatants resulting in substantial cytotoxicity, thereby confirming the specific capability of NK-derived HMGB1 to kill cancer cells (Fig. 2a).